The leaf plastochron serves as an indicator of the rate of leaf appearance, biomass accumulation, and branch number, while also impacting plant architecture and seed yield. However, research on the leaf plastochron of crops remains limited. In this study, 2116C exhibited a rapid leaf plastochron compared to ZH18 during both rosette and bud periods. There were significant positive correlations among the leaf plastochron and primary branch number of the F₂ populations (r ranging from 0.395 to 0.635, p < 0.01). Genetic analyses over two years demonstrated that two equally dominant genes might govern the leaf plastochron. Through bulk segregant analysis sequencing (BSA-seq), three novel genomic intervals were identified on chromosomes A02 (9.04–9.48 Mb and 13.52–13.66 Mb) and A04 (19.84–20.14 Mb) of ZS11 and Darmor-bzh reference genomes. By gene functional annotations, single-nucleotide variation (SNV) analyses, transcriptome data from parents, genetic progeny, and natural accessions, we identified ten candidate genes within the intervals, including FLOWERING LOCUS T, RGL1, MYB-like, CYP96A8, BLH3, NIT2, ASK6, and three CLAVATA3/ESR (CLE)-related genes. These findings lay the molecular foundation for further exploration into the leaf plastochron and the implications in plastochron-related breeding in rapeseed.

Winter rapeseed is susceptible to freezing stress during winter, making it difficult to overwinter safely and resulting in a reduction of yield and quality. DNA methylation, the main epigenetic modification, can regulate plant responses to various stresses. However, the regulatory mechanism of DNA methylation in response to freezing stress in winter rapeseed remains unclear. This study investigates how DNA methylation regulates gene expression and protein abundance in response to freezing stress, revealing key regulatory pathways involved in rapeseed cold tolerance. A total of 6776 unique differentially methylated genes (DMGs), 4285 unique differentially expressed genes (DEGs), and 269 unique differentially abundant proteins (DAPs) were identified between the two cultivars under T1 and T2 freezing stress. Function enrichment analysis revealed that these genes were involved in signal transduction, biosynthesis of unsaturated fatty acids, sugar metabolism, peroxidase, peroxisome, photosynthesis, and additional pathways. An integrative analysis of methylome, transcriptome, and proteome showed that only nine genes were shared among all three datasets, and they were closely related to cold tolerance metabolism in rapeseed. The findings provide molecular insights into rapeseed freezing tolerance, which can be applied in breeding programs to enhance cold resistance in oilseed crops.

Winter rapeseed (Brassica rapa L.) is an important crop for vegetable oil production in China. However, its productivity is frequently threatened by severe cold waves during winter. To investigate the role of the microtubule cytoskeleton in cold adaptation of winter rapeseed, a microtubule stabilizer paclitaxel (Tax) and a microtubule depolymerizer colchicine (Col) were sprayed on winter rapeseed and transgenic proBrAFP1 Arabidopsis, respectively. The mRNA levels of cold-induced genes, along with cell membrane stability, antioxidant enzyme activities, and hormone levels were assessed under cold stresses of 4 °C and −4 °C. The results showed that low temperature significantly activated the proBrAFP1 promoter activity and increased the mRNA levels of core cold signaling pathway genes, such as C-REPEAT BINDING FACTORS (CBFs), Cyclic Nucleotide-Gated Channel (CNGC), OPEN STOMATA 1 (OST1) and Inducer of CBF EXPRESSION 1 (ICE1). Notably, under low-temperature stress, exogenous application of the microtubule stabilizer Tax markedly suppressed proBrAFP1-driven reporter activity in transgenic Arabidopsis, with consistent inhibition observed across both stem and leaf tissues; meanwhile, the Tax application alleviated reactive oxygen species (ROS) accumulation and mitigated membrane damage. In contrast, under the same low-temperature stress, the Col treatment exacerbated oxidative stress, enhanced lipid peroxidation, and elevated membrane damage. Collectively, these findings establish that microtubule regulators play indispensable roles in the cold stress response of winter rapeseed. It provides new insights into the mechanism by which plant microtubule cytoskeleton regulators mediate the cold response.

Rapeseed (Brassica rapa L.) is the primary oil crop in Xizang. However, its loosely branched structure hinders mechanical harvesting. Improvement in plant architecture is necessary to align with industrial development; however, research on branch angle in rapeseed is limited. The branch angle of compact plant type (S) was smaller than that of the dispersed plant type (F). RNA sequencing and targeted metabolome analyses of branch angles of both plant types were assessed at different branch sites. In the S plant type, IAA (3-Indoleacetic acid) contents were significantly higher than those in F at the five stem locations. Targeted metabolome analysis showed that IAA-glu-diME, IAA-Asp, and ICAld were significantly higher in S than in F. Compared to the F plant type, PIN family genes were associated with auxin transport and SGR family genes were significantly upregulated at the branch sites in S. The LAZY1 expression was significantly upregulated, which may be associated with smaller branch angles. In S, a base mutation in the AuxRR core may be associated with a loss of auxin sensitivity in LAZY1 (LOC103846512), whereas that in the LAZY1 promoter increased auxin sensitivity. This study helps in understanding hormone levels in rapeseed stems and branches to develop compact plant types for superior yield and machine harvesting.